The present invention relates to sonar devices, and in particular, to a flasher type sonar device.
Sonar systems are widely used by anglers in determining the depth of water in a lake or river, as well as the presence and depth of fish. Sonar systems use a transducer to generate a sonar pulse that is directed down through the water. The transducer receives a sonar echo return from the bottom, as well as sonar returns from fish or other objects in the water column located within the sonar beam. The time between the transmission of the sonar pulse and the reception of the sonar return can be used as a measure of the distance from the transducer to the bottom, or the distance of the transducer to the fish. Currently popular fish finders take two different forms. In one form, the fish finder has a liquid crystal display that presents a scrolling picture of the bottom, suspended fish, and submerged structure such as weeds, trees, and the like.
The other form of fish finder (referred to as a flasher) has a circular ring lens with an adjacent scale indicating distance below the transducer. The location of the transducer appears at the top of the ring at the 12 o'clock or 0° position. A motor driven disc or spinner carrying multiple colored light sources rotates behind the lens. As the disc rotates, light is emitted by the light sources at different positions around the ring to represent sonar returns from suspended fish or other objects, as well as from the bottom. The color of the light flashes represents the signal intensity of the sonar return, and the angular position of the flash represents a depth of the fish, object, or bottom from the transducer. Examples of flasher type fish finders are shown in Frederickson et al. U.S. Pat. No. 3,952,279; Yamamoto et al. U.S. Pat. No. 3,964,012; Grilk U.S. Pat. No. 4,644,512; Yamamoto et al. U.S. Pat. No. 5,973,997; Cummings et al. U.S. Pat. No. 6,768,701; Asakura U.S. Pat. No. 6,650,595; and Noda et al. U.S. Pat. No. 7,057,972.